Needle for attaching a tag to an infusion bag using an intermediate knotted thread

ABSTRACT

An improved needle ( 1 ) to attach a filter bag ( 2 ) containing a product for infusion to a pick-up tag ( 3 ) using a thread ( 4 ) knotted at least at one of its end sections ( 5; 6 ) comprises two eyes ( 7, 8 ) located at different distances from the point ( 9 ) of the needle ( 1 ). The first eye ( 7 ) is designed to hook the thread ( 4 ), stretched and retained at the end sections ( 5, 6 ) and to make a loop ( 10 ) in the thread when the needle ( 1 ) is pulled in the direction of its axis ( 1   a ). The second eye ( 8 ), on the other hand, is located closer to the point ( 9 ) and is oriented at right angles to the first eye ( 7 ) so that it can be surrounded by the loop ( 10 ) and can guide an end section ( 5; 6 ) of the thread ( 4 ) across the loop ( 10 ) to make a knot. The needle ( 1 ) also comprises two lengthways grooves ( 11 ) that connect the first eye ( 7 ) to the second eye ( 8 ) and that are especially shaped to accommodate the loop ( 10 ) and to keep it in position while the knot is being formed.

This application is the national phase of international applicationPCT/IB99/01549 filed Sep. 16, 1999 which designated the U.S.

TECHNICAL FIELD

The present invention relates to the manufacture of filter bagscontaining products for infusion such as tea, camomile, or other herbs,each bag being made from filter paper folded over itself, sealed andattached to the pick-up tag by an intermediate thread knotted at theends.

BACKGROUND ART

At the present time, the thread is attached to the filter bag and to thepick-up tag by knotting when high quality filter bags are required,differing from similar kinds of bags in; that all the parts of them thatcome into contact with the infusion cannot have even the least harmfuleffects on health and (also very important from the commercialviewpoint) cannot alter the taste of the infusion. For example, badeffects on health and taste may be produced when the filter paperforming the bag is sealed using hot-melt glue or when the top of the bagis closed using metal staples which are also used to attach the threadto the bag.

The present invention relates in particular to an improved needle of thetype comprising two eyes located at different distances from the needlepoint, the first eye being designed to hook the thread, stretched andretained at the end sections and to make a loop in the thread when theneedle is pulled in the direction of its axis; and the second eye beinglocated closer to the point and oriented at right angles to the firsteye so that it can be surrounded by the loop and can guide an endsection of the thread across the loop to make a knot. A needle of thistype is disclosed in Italian patent application No. BO95 A000J48.

In an improved machine forming the subject matter of another applicationfiled at the same time by the same Applicant, the loop, before beingcrossed by the section of thread that will make the knot, is alsotwisted by turning the needle about its axis one or more times, whichreduces the size of the loop and gradually tightens it around thelateral surface of the needle.

In both these solutions, apart from the constraints posed by the way thethread is hooked to the eye and the extent of the pulling force exertedby the needle itself, the loop adapts to the surface of the needle quitefreely. When the thread is pulled by the needle, the loop assumes a flatconfiguration. As the loop is twisted, the plane in which it originallylay is gradually distorted and the more the loop is twisted, the moreits plane is distorted.

Under certain working conditions, the distortion of the loop against thelateral surface of the needle in this way can result in a not entirelycorrect position of the loop relative to the second eye of the needlewhich, as is well known, acts as a guide for special threading elementsused to insert an end section of the thread into the loop.

Although this problem can be avoided by accurate setting up and frequentadjustment, there is room to improve machines of this kind so that theymaintain the correct setup for a longer time without requiring frequentadjustments.

DISCLOSURE OF THE INVENTION

The present invention has for an object to overcome the above mentionedproblems by providing a needle made in such a way that it can constrainthe loop in a well-defined, geometrical configuration which can becontinuously repeated and which is independent of the amount of pullingforce exerted by the needle and/or of the number of times the loop isturned about the axis of the needle in order to twist it.

According to the invention, this object is achieved by an improvedneedle, made according to the preamble to claim 1, characterized in thatit comprises two lengthways grooves that connect the first eye to thesecond eye and that are especially shaped to accommodate the loop and tokeep it in position while the knot is being formed.

The needle may also have a lateral guide element designed to guide thethread and projecting from the lateral surface of the needle point. Thegiude element engages at least one branch of the looped thread in such away that the loop is twisted in a strictly controlled manner when theneedle is turned about its axis.

The technical characteristics of the invention are described in theclaims below and its advantages are apparent from the detaileddescription which follows with reference to the accompanying drawings,which illustrate a preferred embodiment of the invention and in which:

FIG. 1 is a greatly scaled-up side view of a needle made according tothe present invention;

FIG. 2 is a top plan view of the needle illustrated in FIG. 1;

FIG. 3 is a cross section of the needle through line III—III in FIG. 1;

FIG. 4 is a side view of a detail of the needle viewed from side “A”;

FIG. 5 is a side view from “B” of the needle illustrated in FIG. 1;

FIG. 6 is a side view of the needle corresponding to FIG. 5, rotated by180°;

FIG. 7 is a side view of the needle corresponding to FIG. 1, rotated by180°;

FIG. 8 is a cross section of the needle through line VIII—VIII in FIG.1;

FIGS. 9a, 9 b, 9 c, 9 d schematically illustrate a part of the workingcycle performed by the needle.

With reference to the drawings listed above, the invention relates to animproved needle 1 used to attach a filter bag 2, containing a productfor infusion, to a pick-up tag 3 using an intermediate thread 4 which isknotted at its end sections (5; 6) to the filter bag 2 on one side andto the pick-up tag 3 on the other side, according to a method that ispartly known, and some of the steps of which are schematicallyillustrated in FIGS. 9a, 9 b, 9 c and 9 d.

The needle 1 (FIG. 1) basically comprises an elongated body 20terminating at a sharp point 9. The body 20 is cylindrical at the bottomwhile, near the point 9, its cross section becomes curved or polygonalin shape, as shown in FIGS. 2 and 3.

Close to the point 9 on the body 20, there are two open eyes 7, 8 madeon one side of the needle at different distances from the point 9.

The first eye 7, the one further away from the point 9, is designed tohook the thread 4 and is oriented in such a way that it extends at rightangles to the axis 1 a of the needle 1.

The second eye 8, closer to the point 9, is designed to guide specialthreading elements 21 of the thread 4, as described in more detailbelow. It extends obliquely to the axis 1 a of the needle 1 and isoriented at right angles to the first eye 7.

The needle 1 also comprises two straight, lengthways grooves 11, whichextend longitudinally along the lateral surface of the needle 1 from thepoint 9 and down as far as the farther eye 7 (the first eye). Thegrooves 11 together surround the second eye 8 whose open sideintercommunicates with one of the grooves (see FIGS. 5 and 8).

Looking in more detail (see FIGS. 2 and 3), the grooves 11 are locatedsymmetrically about a plane 12 through the axis of rotation 1 a of theneedle 1 and are offset from the axis 1 a by a given dimension “d1”measured in a direction parallel to the plane 12. Their sidewalls 18 aretapered, converging towards the bottom 18 f of each groove 11 with whichthey form smooth, rounded corners.

The needle 1 further comprises a lateral guide element 14 for the thread4, which projects from the lateral surface 15 of the point 9 of theneedle 1 and which engages at least one branch 16 of the looped portion10 of thread in such a way as to correctly control the way the loop 10is twisted when the needle 1 is turned about its axis 1 a.

The guide element 14 is located on the point 9 of the needle 1, in aposition adjacent to the second eye 8. It also has a planar face 17located on one side of one of the grooves 11 for the thread 4, that is,the groove that intercommunicates with the second eye 8.

The planar face 17 is parallel to the lengthways axis 1 a of the needle1 and is offset from said axis 1 a by a dimension d2 measured in adirection parallel to the plane 12. The dimension d2 is measured on theside of the axis 1 a of the needle 1 opposite that on which dimension d1is measured.

The operation of the needle 1 can be described with reference to theaccompanying illustrations, starting from FIG. 9a, in which two needles1 made according to the invention and used to knot the thread 4 to thefilter bag 2 and to the tag 3, are shown as they are pushed through thefilter bag 2 and the tag 3 in a direction parallel to the axis 1 a ofeach, as indicated by the arrows 22, until the first eye 7 of eachneedle hooks the thread 4 while the latter is being stretched andretained at its end sections 5, 6 according to a method well known toexperts in the trade.

Next, with a movement in the opposite direction, as indicated by thearrows 23 in FIG. 9b, the needles 1 are pulled back out of the filterbag 2 and the tag 3, dragging with them the corresponding end sections5, 6 each of which thus forms a loop 10 hooked to the first eye 7 of thecorresponding needle 1. During this movement, each loop 10 is seated inthe grooves 11 which hold it in such a way that it keeps a well-definedgeometrical shape.

In the next step, illustrated in FIG. 9c, the needles 1 are turnedrepeatedly about their axes 1 a so as to twist the loops 10, thanks alsoto the guide elements 14 made on the needles 1.

After a defined number of turns, which cause the loops 10 to close inagainst the lateral surfaces 15 of the needles 1, and after the eye 8has been suitably oriented relative to the path of the threadingelements 21, each of the latter pushes the corresponding end section 5;6of the thread 4 through the corresponding loop 10 to form a loose knotwhich is then tightened in a manner well-known to experts in the trade.

The invention described can be subject to modifications and variationswashout thereby departing from the scope of the inventive concept.Moreover, all the details of the invention may be substituted bytechnically equivalent elements.

What is claimed is:
 1. A needle to attach a filter bag containing aproduct for infusion to a pick-up tag using an intermediate threadknotted at least at one of its end sections, the needle comprising: twoeyes located at different distances from a point of the needle, thefirst eye being constructed and arranged to hook the thread, stretchedand retained at the end sections and to make a loop in the thread whenthe needle is pulled in the direction of its axis, the second eye beinglocated closer to the point of the needle and oriented at right anglesto the first eye such that it can be surrounded by the loop and canguide an end section of the thread across the loop to make a knot; andtwo lengthways grooves that connect at least the first eye to the secondeye and that are constructed and arranged to accommodate the loop and tokeep it in position while the knot is being formed.
 2. The needleaccording to claim 1, wherein the grooves are straight.
 3. The needleaccording to claim 1, wherein the grooves are located symmetricallyabout a plane through the axis of the needle.
 4. The needle according toclaim 3, wherein the grooves are offset from the axis of the needle by adefined dimension measured in a direction parallel to a plane ofsymmetry of the grooves and passing through the axis of the needle. 5.The needle according to claim 1, wherein its cross section is polygonalin shape.
 6. The needle according to claim 1, further comprising atleast one lateral guide element for the thread, which projects from thelateral surface of the point of the needle and which engages at leastone branch of the looped portion of thread in such a way as to enablethe loop to be twisted when the needle is turned about its axis.
 7. Theneedle according to claim 6, wherein the guide element is located on thepoint of the needle, in a position adjacent to the second eye.
 8. Theneedle according to claim 6, wherein the guide element has a planar facelocated on one side of one of the grooves which accommodate the thread.9. The needle according to claim 8, wherein the planar face is parallelto the axis of the needle and is offset by a dimension measured in adirection parallel to a plane of symmetry of the grooves and passingthrough the axis of the needle.
 10. The needle according to claim 1,wherein the sidewalls of the grooves are tapered and converge towardsthe bottom of each groove.